import type { ComponentInterface, EventEmitter } from '@stencil/core';
import { Component, Element, Event, Host, Method, Prop, State, Watch, h, writeTask } from '@stencil/core';
import { startFocusVisible } from '@utils/focus-visible';
import { getElementRoot, raf, renderHiddenInput } from '@utils/helpers';
import { printIonError, printIonWarning } from '@utils/logging';
import { FOCUS_TRAP_DISABLE_CLASS } from '@utils/overlays';
import { isRTL } from '@utils/rtl';
import { createColorClasses } from '@utils/theme';
import { caretDownSharp, caretUpSharp, chevronBack, chevronDown, chevronForward } from 'ionicons/icons';

import { getIonMode } from '../../global/ionic-global';
import type { Color, Mode, StyleEventDetail } from '../../interface';

import type {
  DatetimePresentation,
  DatetimeChangeEventDetail,
  DatetimeParts,
  TitleSelectedDatesFormatter,
  DatetimeHighlight,
  DatetimeHighlightStyle,
  DatetimeHighlightCallback,
  DatetimeHourCycle,
  FormatOptions,
} from './datetime-interface';
import { isSameDay, warnIfValueOutOfBounds, isBefore, isAfter } from './utils/comparison';
import type { WheelColumnOption } from './utils/data';
import {
  generateMonths,
  getDaysOfMonth,
  getDaysOfWeek,
  getToday,
  getMonthColumnData,
  getDayColumnData,
  getYearColumnData,
  getTimeColumnsData,
  getCombinedDateColumnData,
} from './utils/data';
import { formatValue, getLocalizedDateTime, getLocalizedTime, getMonthAndYear } from './utils/format';
import { isLocaleDayPeriodRTL, isMonthFirstLocale, getNumDaysInMonth, getHourCycle } from './utils/helpers';
import {
  calculateHourFromAMPM,
  convertDataToISO,
  getClosestValidDate,
  getEndOfWeek,
  getNextDay,
  getNextMonth,
  getNextWeek,
  getNextYear,
  getPreviousDay,
  getPreviousMonth,
  getPreviousWeek,
  getPreviousYear,
  getStartOfWeek,
  validateParts,
} from './utils/manipulation';
import {
  clampDate,
  convertToArrayOfNumbers,
  getPartsFromCalendarDay,
  parseAmPm,
  parseDate,
  parseMaxParts,
  parseMinParts,
} from './utils/parse';
import {
  getCalendarDayState,
  getHighlightStyles,
  isDayDisabled,
  isMonthDisabled,
  isNextMonthDisabled,
  isPrevMonthDisabled,
} from './utils/state';
import { checkForPresentationFormatMismatch, warnIfTimeZoneProvided } from './utils/validate';

/**
 * @virtualProp {"ios" | "md"} mode - The mode determines which platform styles to use.
 *
 * @slot title - The title of the datetime.
 * @slot buttons - The buttons in the datetime.
 * @slot time-label - The label for the time selector in the datetime.
 *
 * @part wheel-item - The individual items when using a wheel style layout, or in the
 * month/year picker when using a grid style layout.
 * @part wheel-item active - The currently selected wheel-item.
 *
 * @part time-button - The button that opens the time picker when using a grid style
 * layout with `presentation="date-time"` or `"time-date"`.
 * @part time-button active - The time picker button when the picker is open.
 *
 * @part month-year-button - The button that opens the month/year picker when
 * using a grid style layout.
 *
 * @part calendar-day - The individual buttons that display a day inside of the datetime
 * calendar.
 * @part calendar-day active - The currently selected calendar day.
 * @part calendar-day today - The calendar day that contains the current day.
 * @part calendar-day disabled - The calendar day that is disabled.
 */
@Component({
  tag: 'ion-datetime',
  styleUrls: {
    ios: 'datetime.ios.scss',
    md: 'datetime.md.scss',
  },
  shadow: true,
})
export class Datetime implements ComponentInterface {
  private inputId = `ion-dt-${datetimeIds++}`;
  private calendarBodyRef?: HTMLElement;
  private popoverRef?: HTMLIonPopoverElement;
  private intersectionTrackerRef?: HTMLElement;
  private clearFocusVisible?: () => void;
  private parsedMinuteValues?: number[];
  private parsedHourValues?: number[];
  private parsedMonthValues?: number[];
  private parsedYearValues?: number[];
  private parsedDayValues?: number[];

  private destroyCalendarListener?: () => void;
  private destroyKeyboardMO?: () => void;

  // TODO(FW-2832): types (DatetimeParts causes some errors that need untangling)
  private minParts?: any;
  private maxParts?: any;
  private todayParts!: DatetimeParts;
  private defaultParts!: DatetimeParts;

  private prevPresentation: string | null = null;

  private resolveForceDateScrolling?: () => void;

  @State() showMonthAndYear = false;

  @State() activeParts: DatetimeParts | DatetimeParts[] = [];

  @State() workingParts: DatetimeParts = {
    month: 5,
    day: 28,
    year: 2021,
    hour: 13,
    minute: 52,
    ampm: 'pm',
    isAdjacentDay: false,
  };

  @Element() el!: HTMLIonDatetimeElement;

  @State() isTimePopoverOpen = false;

  /**
   * When defined, will force the datetime to render the month
   * containing the specified date. Currently, this should only
   * be used to enable immediately auto-scrolling to the new month,
   * and should then be reset to undefined once the transition is
   * finished and the forced month is now in view.
   *
   * Applies to grid-style datetimes only.
   */
  @State() forceRenderDate?: DatetimeParts;

  /**
   * The color to use from your application's color palette.
   * Default options are: `"primary"`, `"secondary"`, `"tertiary"`, `"success"`, `"warning"`, `"danger"`, `"light"`, `"medium"`, and `"dark"`.
   * For more information on colors, see [theming](/docs/theming/basics).
   */
  @Prop() color?: Color = 'primary';

  /**
   * The name of the control, which is submitted with the form data.
   */
  @Prop() name: string = this.inputId;

  /**
   * If `true`, the user cannot interact with the datetime.
   */
  @Prop() disabled = false;

  /**
   * Formatting options for dates and times.
   * Should include a 'date' and/or 'time' object, each of which is of type [Intl.DateTimeFormatOptions](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Intl/DateTimeFormat/DateTimeFormat#options).
   *
   */
  @Prop() formatOptions?: FormatOptions;

  @Watch('formatOptions')
  protected formatOptionsChanged() {
    const { el, formatOptions, presentation } = this;
    checkForPresentationFormatMismatch(el, presentation, formatOptions);
    warnIfTimeZoneProvided(el, formatOptions);
  }

  /**
   * If `true`, the datetime appears normal but the selected date cannot be changed.
   */
  @Prop() readonly = false;

  /**
   * Returns if an individual date (calendar day) is enabled or disabled.
   *
   * If `true`, the day will be enabled/interactive.
   * If `false`, the day will be disabled/non-interactive.
   *
   * The function accepts an ISO 8601 date string of a given day.
   * By default, all days are enabled. Developers can use this function
   * to write custom logic to disable certain days.
   *
   * The function is called for each rendered calendar day, for the previous, current and next month.
   * Custom implementations should be optimized for performance to avoid jank.
   */
  @Prop() isDateEnabled?: (dateIsoString: string) => boolean;

  /**
   * If `true`, the datetime calendar displays a six-week (42-day) layout,
   * including days from the previous and next months to fill the grid.
   * These adjacent days are selectable unless disabled.
   */
  @Prop() showAdjacentDays = false;

  @Watch('disabled')
  protected disabledChanged() {
    this.emitStyle();
  }

  /**
   * The minimum datetime allowed. Value must be a date string
   * following the
   * [ISO 8601 datetime format standard](https://www.w3.org/TR/NOTE-datetime),
   * such as `1996-12-19`. The format does not have to be specific to an exact
   * datetime. For example, the minimum could just be the year, such as `1994`.
   * Defaults to the beginning of the year, 100 years ago from today.
   */
  @Prop({ mutable: true }) min?: string;

  @Watch('min')
  protected minChanged() {
    this.processMinParts();
  }

  /**
   * The maximum datetime allowed. Value must be a date string
   * following the
   * [ISO 8601 datetime format standard](https://www.w3.org/TR/NOTE-datetime),
   * `1996-12-19`. The format does not have to be specific to an exact
   * datetime. For example, the maximum could just be the year, such as `1994`.
   * Defaults to the end of this year.
   */
  @Prop({ mutable: true }) max?: string;

  @Watch('max')
  protected maxChanged() {
    this.processMaxParts();
  }

  /**
   * Which values you want to select. `"date"` will show
   * a calendar picker to select the month, day, and year. `"time"`
   * will show a time picker to select the hour, minute, and (optionally)
   * AM/PM. `"date-time"` will show the date picker first and time picker second.
   * `"time-date"` will show the time picker first and date picker second.
   */
  @Prop() presentation: DatetimePresentation = 'date-time';

  @Watch('presentation')
  protected presentationChanged() {
    const { el, formatOptions, presentation } = this;
    checkForPresentationFormatMismatch(el, presentation, formatOptions);
  }

  private get isGridStyle() {
    const { presentation, preferWheel } = this;
    const hasDatePresentation = presentation === 'date' || presentation === 'date-time' || presentation === 'time-date';
    return hasDatePresentation && !preferWheel;
  }

  /**
   * The text to display on the picker's cancel button.
   */
  @Prop() cancelText = 'Cancel';

  /**
   * The text to display on the picker's "Done" button.
   */
  @Prop() doneText = 'Done';

  /**
   * The text to display on the picker's "Clear" button.
   */
  @Prop() clearText = 'Clear';

  /**
   * Values used to create the list of selectable years. By default
   * the year values range between the `min` and `max` datetime inputs. However, to
   * control exactly which years to display, the `yearValues` input can take a number, an array
   * of numbers, or string of comma separated numbers. For example, to show upcoming and
   * recent leap years, then this input's value would be `yearValues="2008,2012,2016,2020,2024"`.
   */
  @Prop() yearValues?: number[] | number | string;
  @Watch('yearValues')
  protected yearValuesChanged() {
    this.parsedYearValues = convertToArrayOfNumbers(this.yearValues);
  }

  /**
   * Values used to create the list of selectable months. By default
   * the month values range from `1` to `12`. However, to control exactly which months to
   * display, the `monthValues` input can take a number, an array of numbers, or a string of
   * comma separated numbers. For example, if only summer months should be shown, then this
   * input value would be `monthValues="6,7,8"`. Note that month numbers do *not* have a
   * zero-based index, meaning January's value is `1`, and December's is `12`.
   */
  @Prop() monthValues?: number[] | number | string;
  @Watch('monthValues')
  protected monthValuesChanged() {
    this.parsedMonthValues = convertToArrayOfNumbers(this.monthValues);
  }

  /**
   * Values used to create the list of selectable days. By default
   * every day is shown for the given month. However, to control exactly which days of
   * the month to display, the `dayValues` input can take a number, an array of numbers, or
   * a string of comma separated numbers. Note that even if the array days have an invalid
   * number for the selected month, like `31` in February, it will correctly not show
   * days which are not valid for the selected month.
   */
  @Prop() dayValues?: number[] | number | string;
  @Watch('dayValues')
  protected dayValuesChanged() {
    this.parsedDayValues = convertToArrayOfNumbers(this.dayValues);
  }

  /**
   * Values used to create the list of selectable hours. By default
   * the hour values range from `0` to `23` for 24-hour, or `1` to `12` for 12-hour. However,
   * to control exactly which hours to display, the `hourValues` input can take a number, an
   * array of numbers, or a string of comma separated numbers.
   */
  @Prop() hourValues?: number[] | number | string;
  @Watch('hourValues')
  protected hourValuesChanged() {
    this.parsedHourValues = convertToArrayOfNumbers(this.hourValues);
  }

  /**
   * Values used to create the list of selectable minutes. By default
   * the minutes range from `0` to `59`. However, to control exactly which minutes to display,
   * the `minuteValues` input can take a number, an array of numbers, or a string of comma
   * separated numbers. For example, if the minute selections should only be every 15 minutes,
   * then this input value would be `minuteValues="0,15,30,45"`.
   */
  @Prop() minuteValues?: number[] | number | string;
  @Watch('minuteValues')
  protected minuteValuesChanged() {
    this.parsedMinuteValues = convertToArrayOfNumbers(this.minuteValues);
  }

  /**
   * The locale to use for `ion-datetime`. This
   * impacts month and day name formatting.
   * The `"default"` value refers to the default
   * locale set by your device.
   */
  @Prop() locale = 'default';

  /**
   * The first day of the week to use for `ion-datetime`. The
   * default value is `0` and represents Sunday.
   */
  @Prop() firstDayOfWeek = 0;

  /**
   * A callback used to format the header text that shows how many
   * dates are selected. Only used if there are 0 or more than 1
   * selected (i.e. unused for exactly 1). By default, the header
   * text is set to "numberOfDates days".
   *
   * See https://ionicframework.com/docs/troubleshooting/runtime#accessing-this
   * if you need to access `this` from within the callback.
   */
  @Prop() titleSelectedDatesFormatter?: TitleSelectedDatesFormatter;

  /**
   * If `true`, multiple dates can be selected at once. Only
   * applies to `presentation="date"` and `preferWheel="false"`.
   */
  @Prop() multiple = false;

  /**
   * Used to apply custom text and background colors to specific dates.
   *
   * Can be either an array of objects containing ISO strings and colors,
   * or a callback that receives an ISO string and returns the colors.
   *
   * Only applies to the `date`, `date-time`, and `time-date` presentations,
   * with `preferWheel="false"`.
   */
  @Prop() highlightedDates?: DatetimeHighlight[] | DatetimeHighlightCallback;

  /**
   * The value of the datetime as a valid ISO 8601 datetime string.
   * This should be an array of strings only when `multiple="true"`.
   */
  @Prop({ mutable: true }) value?: string | string[] | null;

  /**
   * Update the datetime value when the value changes
   */
  @Watch('value')
  protected async valueChanged() {
    const { value } = this;

    if (this.hasValue()) {
      this.processValue(value);
    }

    this.emitStyle();
    this.ionValueChange.emit({ value });
  }

  /**
   * If `true`, a header will be shown above the calendar
   * picker. This will include both the slotted title, and
   * the selected date.
   */
  @Prop() showDefaultTitle = false;

  /**
   * If `true`, the default "Cancel" and "OK" buttons
   * will be rendered at the bottom of the `ion-datetime`
   * component. Developers can also use the `button` slot
   * if they want to customize these buttons. If custom
   * buttons are set in the `button` slot then the
   * default buttons will not be rendered.
   */
  @Prop() showDefaultButtons = false;

  /**
   * If `true`, a "Clear" button will be rendered alongside
   * the default "Cancel" and "OK" buttons at the bottom of the `ion-datetime`
   * component. Developers can also use the `button` slot
   * if they want to customize these buttons. If custom
   * buttons are set in the `button` slot then the
   * default buttons will not be rendered.
   */
  @Prop() showClearButton = false;

  /**
   * If `true`, the default "Time" label will be rendered
   * for the time selector of the `ion-datetime` component.
   * Developers can also use the `time-label` slot
   * if they want to customize this label. If a custom
   * label is set in the `time-label` slot then the
   * default label will not be rendered.
   */
  @Prop() showDefaultTimeLabel = true;

  /**
   * The hour cycle of the `ion-datetime`. If no value is set, this is
   * specified by the current locale.
   */
  @Prop() hourCycle?: DatetimeHourCycle;

  /**
   * If `cover`, the `ion-datetime` will expand to cover the full width of its container.
   * If `fixed`, the `ion-datetime` will have a fixed width.
   */
  @Prop() size: 'cover' | 'fixed' = 'fixed';

  /**
   * If `true`, a wheel picker will be rendered instead of a calendar grid
   * where possible. If `false`, a calendar grid will be rendered instead of
   * a wheel picker where possible.
   *
   * A wheel picker can be rendered instead of a grid when `presentation` is
   * one of the following values: `"date"`, `"date-time"`, or `"time-date"`.
   *
   * A wheel picker will always be rendered regardless of
   * the `preferWheel` value when `presentation` is one of the following values:
   * `"time"`, `"month"`, `"month-year"`, or `"year"`.
   */
  @Prop() preferWheel = false;

  /**
   * Emitted when the datetime selection was cancelled.
   */
  @Event() ionCancel!: EventEmitter<void>;

  /**
   * Emitted when the value (selected date) has changed.
   *
   * This event will not emit when programmatically setting the `value` property.
   */
  @Event() ionChange!: EventEmitter<DatetimeChangeEventDetail>;

  /**
   * Emitted when the value property has changed.
   * This is used to ensure that ion-datetime-button can respond
   * to any value property changes.
   * @internal
   */
  @Event() ionValueChange!: EventEmitter<DatetimeChangeEventDetail>;

  /**
   * Emitted when the datetime has focus.
   */
  @Event() ionFocus!: EventEmitter<void>;

  /**
   * Emitted when the datetime loses focus.
   */
  @Event() ionBlur!: EventEmitter<void>;

  /**
   * Emitted when the styles change.
   * @internal
   */
  @Event() ionStyle!: EventEmitter<StyleEventDetail>;

  /**
   * Emitted when componentDidRender is fired.
   * @internal
   */
  @Event() ionRender!: EventEmitter<void>;

  /**
   * Confirms the selected datetime value, updates the
   * `value` property, and optionally closes the popover
   * or modal that the datetime was presented in.
   *
   * @param closeOverlay If `true`, closes the parent overlay. Defaults to `false`.
   */
  @Method()
  async confirm(closeOverlay = false) {
    const { isCalendarPicker, activeParts, preferWheel, workingParts } = this;

    /**
     * We only update the value if the presentation is not a calendar picker.
     */
    if (activeParts !== undefined || !isCalendarPicker) {
      const activePartsIsArray = Array.isArray(activeParts);
      if (activePartsIsArray && activeParts.length === 0) {
        if (preferWheel) {
          /**
           * If the datetime is using a wheel picker, but the
           * active parts are empty, then the user has confirmed the
           * initial value (working parts) presented to them.
           */
          this.setValue(convertDataToISO(workingParts));
        } else {
          this.setValue(undefined);
        }
      } else {
        this.setValue(convertDataToISO(activeParts));
      }
    }

    if (closeOverlay) {
      this.closeParentOverlay(CONFIRM_ROLE);
    }
  }

  /**
   * Resets the internal state of the datetime but does not update the value.
   * Passing a valid ISO-8601 string will reset the state of the component to the provided date.
   * If no value is provided, the internal state will be reset to the clamped value of the min, max and today.
   *
   * @param startDate A valid [ISO-8601 string](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Date#date_time_string_format) to reset the datetime state to.
   */
  @Method()
  async reset(startDate?: string) {
    this.processValue(startDate);
  }

  /**
   * Emits the ionCancel event and
   * optionally closes the popover
   * or modal that the datetime was
   * presented in.
   *
   * @param closeOverlay If `true`, closes the parent overlay. Defaults to `false`.
   */
  @Method()
  async cancel(closeOverlay = false) {
    this.ionCancel.emit();

    if (closeOverlay) {
      this.closeParentOverlay(CANCEL_ROLE);
    }
  }

  private warnIfIncorrectValueUsage = () => {
    const { multiple, value } = this;
    if (!multiple && Array.isArray(value)) {
      /**
       * We do some processing on the `value` array so
       * that it looks more like an array when logged to
       * the console.
       * Example given ['a', 'b']
       * Default toString() behavior: a,b
       * Custom behavior: ['a', 'b']
       */
      printIonWarning(
        `[ion-datetime] - An array of values was passed, but multiple is "false". This is incorrect usage and may result in unexpected behaviors. To dismiss this warning, pass a string to the "value" property when multiple="false".

  Value Passed: [${value.map((v) => `'${v}'`).join(', ')}]
`,
        this.el
      );
    }
  };

  private setValue = (value?: string | string[] | null) => {
    this.value = value;
    this.ionChange.emit({ value });
  };

  /**
   * Returns the DatetimePart interface
   * to use when rendering an initial set of
   * data. This should be used when rendering an
   * interface in an environment where the `value`
   * may not be set. This function works
   * by returning the first selected date and then
   * falling back to defaultParts if no active date
   * is selected.
   */
  private getActivePartsWithFallback = () => {
    const { defaultParts } = this;
    return this.getActivePart() ?? defaultParts;
  };

  private getActivePart = () => {
    const { activeParts } = this;
    return Array.isArray(activeParts) ? activeParts[0] : activeParts;
  };

  private closeParentOverlay = (role: string) => {
    const popoverOrModal = this.el.closest('ion-modal, ion-popover') as
      | HTMLIonModalElement
      | HTMLIonPopoverElement
      | null;
    if (popoverOrModal) {
      popoverOrModal.dismiss(undefined, role);
    }
  };

  private setWorkingParts = (parts: DatetimeParts) => {
    this.workingParts = {
      ...parts,
    };
  };

  private setActiveParts = (parts: DatetimeParts, removeDate = false) => {
    /** if the datetime component is in readonly mode,
     * allow browsing of the calendar without changing
     * the set value
     */
    if (this.readonly) {
      return;
    }

    const { multiple, minParts, maxParts, activeParts } = this;

    /**
     * When setting the active parts, it is possible
     * to set invalid data. For example,
     * when updating January 31 to February,
     * February 31 does not exist. As a result
     * we need to validate the active parts and
     * ensure that we are only setting valid dates.
     * Additionally, we need to update the working parts
     * too in the event that the validated parts are different.
     */
    const validatedParts = validateParts(parts, minParts, maxParts);
    this.setWorkingParts(validatedParts);

    if (multiple) {
      const activePartsArray = Array.isArray(activeParts) ? activeParts : [activeParts];
      if (removeDate) {
        this.activeParts = activePartsArray.filter((p) => !isSameDay(p, validatedParts));
      } else {
        this.activeParts = [...activePartsArray, validatedParts];
      }
    } else {
      this.activeParts = {
        ...validatedParts,
      };
    }

    const hasSlottedButtons = this.el.querySelector('[slot="buttons"]') !== null;
    if (hasSlottedButtons || this.showDefaultButtons) {
      return;
    }

    this.confirm();
  };

  private get isCalendarPicker() {
    const { presentation } = this;
    return presentation === 'date' || presentation === 'date-time' || presentation === 'time-date';
  }

  private initializeKeyboardListeners = () => {
    const calendarBodyRef = this.calendarBodyRef;
    if (!calendarBodyRef) {
      return;
    }

    const root = this.el!.shadowRoot!;

    /**
     * Get a reference to the month
     * element we are currently viewing.
     */
    const currentMonth = calendarBodyRef.querySelector('.calendar-month:nth-of-type(2)')!;

    /**
     * When focusing the calendar body, we want to pass focus
     * to the working day, but other days should
     * only be accessible using the arrow keys. Pressing
     * Tab should jump between bodies of selectable content.
     */
    const checkCalendarBodyFocus = (ev: MutationRecord[]) => {
      const record = ev[0];

      /**
       * If calendar body was already focused
       * when this fired or if the calendar body
       * if not currently focused, we should not re-focus
       * the inner day.
       */
      if (record.oldValue?.includes('ion-focused') || !calendarBodyRef.classList.contains('ion-focused')) {
        return;
      }

      this.focusWorkingDay(currentMonth);
    };
    const mo = new MutationObserver(checkCalendarBodyFocus);
    mo.observe(calendarBodyRef, { attributeFilter: ['class'], attributeOldValue: true });

    this.destroyKeyboardMO = () => {
      mo?.disconnect();
    };

    /**
     * We must use keydown not keyup as we want
     * to prevent scrolling when using the arrow keys.
     */
    calendarBodyRef.addEventListener('keydown', (ev: KeyboardEvent) => {
      const activeElement = root.activeElement;
      if (!activeElement || !activeElement.classList.contains('calendar-day')) {
        return;
      }

      const parts = getPartsFromCalendarDay(activeElement as HTMLElement);

      let partsToFocus: DatetimeParts | undefined;
      switch (ev.key) {
        case 'ArrowDown':
          ev.preventDefault();
          partsToFocus = getNextWeek(parts);
          break;
        case 'ArrowUp':
          ev.preventDefault();
          partsToFocus = getPreviousWeek(parts);
          break;
        case 'ArrowRight':
          ev.preventDefault();
          partsToFocus = getNextDay(parts);
          break;
        case 'ArrowLeft':
          ev.preventDefault();
          partsToFocus = getPreviousDay(parts);
          break;
        case 'Home':
          ev.preventDefault();
          partsToFocus = getStartOfWeek(parts);
          break;
        case 'End':
          ev.preventDefault();
          partsToFocus = getEndOfWeek(parts);
          break;
        case 'PageUp':
          ev.preventDefault();
          partsToFocus = ev.shiftKey ? getPreviousYear(parts) : getPreviousMonth(parts);
          break;
        case 'PageDown':
          ev.preventDefault();
          partsToFocus = ev.shiftKey ? getNextYear(parts) : getNextMonth(parts);
          break;
        /**
         * Do not preventDefault here
         * as we do not want to override other
         * browser defaults such as pressing Enter/Space
         * to select a day.
         */
        default:
          return;
      }

      /**
       * If the day we want to move focus to is
       * disabled, do not do anything.
       */
      if (isDayDisabled(partsToFocus, this.minParts, this.maxParts)) {
        return;
      }

      this.setWorkingParts({
        ...this.workingParts,
        ...partsToFocus,
      });

      /**
       * Give view a chance to re-render
       * then move focus to the new working day
       */
      requestAnimationFrame(() => this.focusWorkingDay(currentMonth));
    });
  };

  private focusWorkingDay = (currentMonth: Element) => {
    /**
     * Get the number of offset days so
     * we know how much to offset our next selector by
     * to grab the correct calendar-day element.
     */

    const { day, month, year } = this.workingParts;
    const firstOfMonth = new Date(`${month}/1/${year}`).getDay();
    const offset =
      firstOfMonth >= this.firstDayOfWeek
        ? firstOfMonth - this.firstDayOfWeek
        : 7 - (this.firstDayOfWeek - firstOfMonth);

    if (day === null) {
      return;
    }

    /**
     * Get the calendar day element
     * and focus it.
     */
    const dayEl = currentMonth.querySelector(
      `.calendar-day-wrapper:nth-of-type(${offset + day}) .calendar-day`
    ) as HTMLElement | null;
    if (dayEl) {
      dayEl.focus();
    }
  };

  private processMinParts = () => {
    const { min, defaultParts } = this;
    if (min === undefined) {
      this.minParts = undefined;
      return;
    }

    this.minParts = parseMinParts(min, defaultParts);
  };

  private processMaxParts = () => {
    const { max, defaultParts } = this;

    if (max === undefined) {
      this.maxParts = undefined;
      return;
    }

    this.maxParts = parseMaxParts(max, defaultParts);
  };

  private initializeCalendarListener = () => {
    const calendarBodyRef = this.calendarBodyRef;
    if (!calendarBodyRef) {
      return;
    }

    /**
     * For performance reasons, we only render 3
     * months at a time: The current month, the previous
     * month, and the next month. We have a scroll listener
     * on the calendar body to append/prepend new months.
     *
     * We can do this because Stencil is smart enough to not
     * re-create the .calendar-month containers, but rather
     * update the content within those containers.
     *
     * As an added bonus, WebKit has some troubles with
     * scroll-snap-stop: always, so not rendering all of
     * the months in a row allows us to mostly sidestep
     * that issue.
     */
    const months = calendarBodyRef.querySelectorAll('.calendar-month');

    const startMonth = months[0] as HTMLElement;
    const workingMonth = months[1] as HTMLElement;
    const endMonth = months[2] as HTMLElement;
    const mode = getIonMode(this);
    const needsiOSRubberBandFix = mode === 'ios' && typeof navigator !== 'undefined' && navigator.maxTouchPoints > 1;

    /**
     * Before setting up the scroll listener,
     * scroll the middle month into view.
     * scrollIntoView() will scroll entire page
     * if element is not in viewport. Use scrollLeft instead.
     */
    writeTask(() => {
      calendarBodyRef.scrollLeft = startMonth.clientWidth * (isRTL(this.el) ? -1 : 1);

      const getChangedMonth = (parts: DatetimeParts): DatetimeParts | undefined => {
        const box = calendarBodyRef.getBoundingClientRect();

        /**
         * If the current scroll position is all the way to the left
         * then we have scrolled to the previous month.
         * Otherwise, assume that we have scrolled to the next
         * month. We have a tolerance of 2px to account for
         * sub pixel rendering.
         *
         * Check below the next line ensures that we did not
         * swipe and abort (i.e. we swiped but we are still on the current month).
         */
        const condition = isRTL(this.el) ? calendarBodyRef.scrollLeft >= -2 : calendarBodyRef.scrollLeft <= 2;
        const month = condition ? startMonth : endMonth;

        /**
         * The edge of the month must be lined up with
         * the edge of the calendar body in order for
         * the component to update. Otherwise, it
         * may be the case that the user has paused their
         * swipe or the browser has not finished snapping yet.
         * Rather than check if the x values are equal,
         * we give it a tolerance of 2px to account for
         * sub pixel rendering.
         */
        const monthBox = month.getBoundingClientRect();
        if (Math.abs(monthBox.x - box.x) > 2) return;

        /**
         * If we're force-rendering a month, assume we've
         * scrolled to that and return it.
         *
         * If forceRenderDate is ever used in a context where the
         * forced month is not immediately auto-scrolled to, this
         * should be updated to also check whether `month` has the
         * same month and year as the forced date.
         */
        const { forceRenderDate } = this;
        if (forceRenderDate !== undefined) {
          return { month: forceRenderDate.month, year: forceRenderDate.year, day: forceRenderDate.day };
        }

        /**
         * From here, we can determine if the start
         * month or the end month was scrolled into view.
         * If no month was changed, then we can return from
         * the scroll callback early.
         */
        if (month === startMonth) {
          return getPreviousMonth(parts);
        } else if (month === endMonth) {
          return getNextMonth(parts);
        } else {
          return;
        }
      };

      const updateActiveMonth = () => {
        if (needsiOSRubberBandFix) {
          calendarBodyRef.style.removeProperty('pointer-events');
          appliediOSRubberBandFix = false;
        }

        /**
         * If the month did not change
         * then we can return early.
         */
        const newDate = getChangedMonth(this.workingParts);
        if (!newDate) return;

        const { month, day, year } = newDate;

        if (
          isMonthDisabled(
            { month, year, day: null },
            {
              minParts: { ...this.minParts, day: null },
              maxParts: { ...this.maxParts, day: null },
            }
          )
        ) {
          return;
        }

        /**
         * Prevent scrolling for other browsers
         * to give the DOM time to update and the container
         * time to properly snap.
         */
        calendarBodyRef.style.setProperty('overflow', 'hidden');

        /**
         * Use a writeTask here to ensure
         * that the state is updated and the
         * correct month is scrolled into view
         * in the same frame. This is not
         * typically a problem on newer devices
         * but older/slower device may have a flicker
         * if we did not do this.
         */
        writeTask(() => {
          this.setWorkingParts({
            ...this.workingParts,
            month,
            day: day!,
            year,
          });

          calendarBodyRef.scrollLeft = workingMonth.clientWidth * (isRTL(this.el) ? -1 : 1);
          calendarBodyRef.style.removeProperty('overflow');

          if (this.resolveForceDateScrolling) {
            this.resolveForceDateScrolling();
          }
        });
      };

      /**
       * When the container finishes scrolling we
       * need to update the DOM with the selected month.
       */
      let scrollTimeout: ReturnType<typeof setTimeout> | undefined;

      /**
       * We do not want to attempt to set pointer-events
       * multiple times within a single swipe gesture as
       * that adds unnecessary work to the main thread.
       */
      let appliediOSRubberBandFix = false;
      const scrollCallback = () => {
        if (scrollTimeout) {
          clearTimeout(scrollTimeout);
        }

        /**
         * On iOS it is possible to quickly rubber band
         * the scroll area before the scroll timeout has fired.
         * This results in users reaching the end of the scrollable
         * container before the DOM has updated.
         * By setting `pointer-events: none` we can ensure that
         * subsequent swipes do not happen while the container
         * is snapping.
         */
        if (!appliediOSRubberBandFix && needsiOSRubberBandFix) {
          calendarBodyRef.style.setProperty('pointer-events', 'none');
          appliediOSRubberBandFix = true;
        }

        // Wait ~3 frames
        scrollTimeout = setTimeout(updateActiveMonth, 50);
      };

      calendarBodyRef.addEventListener('scroll', scrollCallback);

      this.destroyCalendarListener = () => {
        calendarBodyRef.removeEventListener('scroll', scrollCallback);
      };
    });
  };

  connectedCallback() {
    this.clearFocusVisible = startFocusVisible(this.el).destroy;
  }

  disconnectedCallback() {
    if (this.clearFocusVisible) {
      this.clearFocusVisible();
      this.clearFocusVisible = undefined;
    }
  }

  /**
   * Clean up all listeners except for the overlay
   * listener. This is so that we can re-create the listeners
   * if the datetime has been hidden/presented by a modal or popover.
   */
  private destroyInteractionListeners = () => {
    const { destroyCalendarListener, destroyKeyboardMO } = this;

    if (destroyCalendarListener !== undefined) {
      destroyCalendarListener();
    }

    if (destroyKeyboardMO !== undefined) {
      destroyKeyboardMO();
    }
  };

  private initializeListeners() {
    this.initializeCalendarListener();
    this.initializeKeyboardListeners();
  }

  /**
   * TODO(FW-6931): Remove this fallback upon solving the root cause
   * Fallback to ensure the datetime becomes ready even if
   * IntersectionObserver never reports it as intersecting.
   *
   * This is primarily used in environments where the observer
   * might not fire as expected, such as when running under
   * synthetic tests that stub IntersectionObserver.
   */
  private ensureReadyIfVisible = () => {
    if (this.el.classList.contains('datetime-ready')) {
      return;
    }

    const rect = this.el.getBoundingClientRect();
    if (rect.width === 0 || rect.height === 0) {
      return;
    }

    this.initializeListeners();

    writeTask(() => {
      this.el.classList.add('datetime-ready');
    });
  };

  componentDidLoad() {
    const { el, intersectionTrackerRef } = this;

    /**
     * If a scrollable element is hidden using `display: none`,
     * it will not have a scroll height meaning we cannot scroll elements
     * into view. As a result, we will need to wait for the datetime to become
     * visible if used inside of a modal or a popover otherwise the scrollable
     * areas will not have the correct values snapped into place.
     */
    const visibleCallback = (entries: IntersectionObserverEntry[]) => {
      const ev = entries[0];
      if (!ev.isIntersecting) {
        return;
      }

      this.initializeListeners();

      /**
       * TODO FW-2793: Datetime needs a frame to ensure that it
       * can properly scroll contents into view. As a result
       * we hide the scrollable content until after that frame
       * so users do not see the content quickly shifting. The downside
       * is that the content will pop into view a frame after. Maybe there
       * is a better way to handle this?
       */
      writeTask(() => {
        this.el.classList.add('datetime-ready');
      });
    };
    const visibleIO = new IntersectionObserver(visibleCallback, { threshold: 0.01, root: el });

    /**
     * Use raf to avoid a race condition between the component loading and
     * its display animation starting (such as when shown in a modal). This
     * could cause the datetime to start at a visibility of 0, erroneously
     * triggering the `hiddenIO` observer below.
     */
    raf(() => visibleIO?.observe(intersectionTrackerRef!));

    /**
     * TODO(FW-6931): Remove this fallback upon solving the root cause
     * Fallback: If IntersectionObserver never reports that the
     * datetime is visible but the host clearly has layout, ensure
     * we still initialize listeners and mark the component as ready.
     *
     * We schedule this after everything has had a chance to run.
     */
    setTimeout(() => {
      this.ensureReadyIfVisible();
    }, 100);

    /**
     * We need to clean up listeners when the datetime is hidden
     * in a popover/modal so that we can properly scroll containers
     * back into view if they are re-presented. When the datetime is hidden
     * the scroll areas have scroll widths/heights of 0px, so any snapping
     * we did originally has been lost.
     */
    const hiddenCallback = (entries: IntersectionObserverEntry[]) => {
      const ev = entries[0];
      if (ev.isIntersecting) {
        return;
      }

      this.destroyInteractionListeners();

      /**
       * When datetime is hidden, we need to make sure that
       * the month/year picker is closed. Otherwise,
       * it will be open when the datetime re-appears
       * and the scroll area of the calendar grid will be 0.
       * As a result, the wrong month will be shown.
       */
      this.showMonthAndYear = false;

      writeTask(() => {
        this.el.classList.remove('datetime-ready');
      });
    };
    const hiddenIO = new IntersectionObserver(hiddenCallback, { threshold: 0, root: el });
    raf(() => hiddenIO?.observe(intersectionTrackerRef!));

    /**
     * Datetime uses Ionic components that emit
     * ionFocus and ionBlur. These events are
     * composed meaning they will cross
     * the shadow dom boundary. We need to
     * stop propagation on these events otherwise
     * developers will see 2 ionFocus or 2 ionBlur
     * events at a time.
     */
    const root = getElementRoot(this.el);
    root.addEventListener('ionFocus', (ev: Event) => ev.stopPropagation());
    root.addEventListener('ionBlur', (ev: Event) => ev.stopPropagation());
  }

  /**
   * When the presentation is changed, all calendar content is recreated,
   * so we need to re-init behavior with the new elements.
   */
  componentDidRender() {
    const { presentation, prevPresentation, calendarBodyRef, minParts, preferWheel, forceRenderDate } = this;

    /**
     * TODO(FW-2165)
     * Remove this when https://bugs.webkit.org/show_bug.cgi?id=235960 is fixed.
     * When using `min`, we add `scroll-snap-align: none`
     * to the disabled month so that users cannot scroll to it.
     * This triggers a bug in WebKit where the scroll position is reset.
     * Since the month change logic is handled by a scroll listener,
     * this causes the month to change leading to `scroll-snap-align`
     * changing again, thus changing the scroll position again and causing
     * an infinite loop.
     * This issue only applies to the calendar grid, so we can disable
     * it if the calendar grid is not being used.
     */
    const hasCalendarGrid = !preferWheel && ['date-time', 'time-date', 'date'].includes(presentation);
    if (minParts !== undefined && hasCalendarGrid && calendarBodyRef) {
      const workingMonth = calendarBodyRef.querySelector('.calendar-month:nth-of-type(1)');
      /**
       * We need to make sure the datetime is not in the process
       * of scrolling to a new datetime value if the value
       * is updated programmatically.
       * Otherwise, the datetime will appear to not scroll at all because
       * we are resetting the scroll position to the center of the view.
       * Prior to the datetime's value being updated programmatically,
       * the calendarBodyRef is scrolled such that the middle month is centered
       * in the view. The below code updates the scroll position so the middle
       * month is also centered in the view. Since the scroll position did not change,
       * the scroll callback in this file does not fire,
       * and the resolveForceDateScrolling promise never resolves.
       */
      if (workingMonth && forceRenderDate === undefined) {
        calendarBodyRef.scrollLeft = workingMonth.clientWidth * (isRTL(this.el) ? -1 : 1);
      }
    }

    if (prevPresentation === null) {
      this.prevPresentation = presentation;
      return;
    }

    if (presentation === prevPresentation) {
      return;
    }
    this.prevPresentation = presentation;

    this.destroyInteractionListeners();

    this.initializeListeners();

    /**
     * The month/year picker from the date interface
     * should be closed as it is not available in non-date
     * interfaces.
     */
    this.showMonthAndYear = false;

    raf(() => {
      this.ionRender.emit();
    });
  }

  private processValue = (value?: string | string[] | null) => {
    const hasValue =
      value !== null && value !== undefined && value !== '' && (!Array.isArray(value) || value.length > 0);
    const valueToProcess = hasValue ? parseDate(value) : this.defaultParts;

    const { minParts, maxParts, workingParts, el } = this;

    this.warnIfIncorrectValueUsage();

    /**
     * Return early if the value wasn't parsed correctly, such as
     * if an improperly formatted date string was provided.
     */
    if (!valueToProcess) {
      return;
    }

    /**
     * Datetime should only warn of out of bounds values
     * if set by the user. If the `value` is undefined,
     * we will default to today's date which may be out
     * of bounds. In this case, the warning makes it look
     * like the developer did something wrong which is
     * not true.
     */
    if (hasValue) {
      warnIfValueOutOfBounds(valueToProcess, minParts, maxParts);
    }

    /**
     * If there are multiple values, clamp to the last one.
     * This is because the last value is the one that the user
     * has most recently interacted with.
     */
    const singleValue = Array.isArray(valueToProcess) ? valueToProcess[valueToProcess.length - 1] : valueToProcess;
    const targetValue = clampDate(singleValue, minParts, maxParts);

    const { month, day, year, hour, minute } = targetValue;
    const ampm = parseAmPm(hour!);

    /**
     * Since `activeParts` indicates a value that been explicitly selected
     * either by the user or the app, only update `activeParts` if the
     * `value` property is set.
     */
    if (hasValue) {
      if (Array.isArray(valueToProcess)) {
        this.activeParts = [...valueToProcess];
      } else {
        this.activeParts = {
          month,
          day,
          year,
          hour,
          minute,
          ampm,
        };
      }
    } else {
      /**
       * Reset the active parts if the value is not set.
       * This will clear the selected calendar day when
       * performing a clear action or using the reset() method.
       */
      this.activeParts = [];
    }

    const didChangeMonth =
      (month !== undefined && month !== workingParts.month) || (year !== undefined && year !== workingParts.year);
    const bodyIsVisible = el.classList.contains('datetime-ready');
    const { isGridStyle, showMonthAndYear } = this;

    if (isGridStyle && didChangeMonth && bodyIsVisible && !showMonthAndYear) {
      /**
       * Only animate if:
       * 1. We're using grid style (wheel style pickers should just jump to new value)
       * 2. The month and/or year actually changed, and both are defined (otherwise there's nothing to animate to)
       * 3. The calendar body is visible (prevents animation when in collapsed datetime-button, for example)
       * 4. The month/year picker is not open (since you wouldn't see the animation anyway)
       */
      this.animateToDate(targetValue);
    } else {
      this.setWorkingParts({
        month,
        day,
        year,
        hour,
        minute,
        ampm,
      });
    }
  };

  private animateToDate = async (targetValue: DatetimeParts) => {
    const { workingParts } = this;

    /**
     * Tell other render functions that we need to force the
     * target month to appear in place of the actual next/prev month.
     * Because this is a State variable, a rerender will be triggered
     * automatically, updating the rendered months.
     */
    this.forceRenderDate = targetValue;

    /**
     * Flag that we've started scrolling to the forced date.
     * The resolve function will be called by the datetime's
     * scroll listener when it's done updating everything.
     * This is a replacement for making prev/nextMonth async,
     * since the logic we're waiting on is in a listener.
     */
    const forceDateScrollingPromise = new Promise<void>((resolve) => {
      this.resolveForceDateScrolling = resolve;
    });

    /**
     * Animate smoothly to the forced month. This will also update
     * workingParts and correct the surrounding months for us.
     */
    const targetMonthIsBefore = isBefore(targetValue, workingParts);
    targetMonthIsBefore ? this.prevMonth() : this.nextMonth();
    await forceDateScrollingPromise;
    this.resolveForceDateScrolling = undefined;
    this.forceRenderDate = undefined;
  };

  componentWillLoad() {
    const { el, formatOptions, highlightedDates, multiple, presentation, preferWheel } = this;

    if (multiple) {
      if (presentation !== 'date') {
        printIonWarning('[ion-datetime] - Multiple date selection is only supported for presentation="date".', el);
      }

      if (preferWheel) {
        printIonWarning('[ion-datetime] - Multiple date selection is not supported with preferWheel="true".', el);
      }
    }

    if (highlightedDates !== undefined) {
      if (presentation !== 'date' && presentation !== 'date-time' && presentation !== 'time-date') {
        printIonWarning(
          '[ion-datetime] - The highlightedDates property is only supported with the date, date-time, and time-date presentations.',
          el
        );
      }

      if (preferWheel) {
        printIonWarning('[ion-datetime] - The highlightedDates property is not supported with preferWheel="true".', el);
      }
    }

    if (formatOptions) {
      checkForPresentationFormatMismatch(el, presentation, formatOptions);
      warnIfTimeZoneProvided(el, formatOptions);
    }

    const hourValues = (this.parsedHourValues = convertToArrayOfNumbers(this.hourValues));
    const minuteValues = (this.parsedMinuteValues = convertToArrayOfNumbers(this.minuteValues));
    const monthValues = (this.parsedMonthValues = convertToArrayOfNumbers(this.monthValues));
    const yearValues = (this.parsedYearValues = convertToArrayOfNumbers(this.yearValues));
    const dayValues = (this.parsedDayValues = convertToArrayOfNumbers(this.dayValues));

    const todayParts = (this.todayParts = parseDate(getToday())!);

    this.processMinParts();
    this.processMaxParts();

    this.defaultParts = getClosestValidDate({
      refParts: todayParts,
      monthValues,
      dayValues,
      yearValues,
      hourValues,
      minuteValues,
      minParts: this.minParts,
      maxParts: this.maxParts,
    });

    this.processValue(this.value);

    this.emitStyle();
  }

  private emitStyle() {
    this.ionStyle.emit({
      interactive: true,
      datetime: true,
      'interactive-disabled': this.disabled,
    });
  }

  private onFocus = () => {
    this.ionFocus.emit();
  };

  private onBlur = () => {
    this.ionBlur.emit();
  };

  private hasValue = () => {
    return this.value != null;
  };

  private nextMonth = () => {
    const calendarBodyRef = this.calendarBodyRef;
    if (!calendarBodyRef) {
      return;
    }

    const nextMonth = calendarBodyRef.querySelector('.calendar-month:last-of-type');
    if (!nextMonth) {
      return;
    }

    const left = (nextMonth as HTMLElement).offsetWidth * 2;

    calendarBodyRef.scrollTo({
      top: 0,
      left: left * (isRTL(this.el) ? -1 : 1),
      behavior: 'smooth',
    });
  };

  private prevMonth = () => {
    const calendarBodyRef = this.calendarBodyRef;
    if (!calendarBodyRef) {
      return;
    }

    const prevMonth = calendarBodyRef.querySelector('.calendar-month:first-of-type');
    if (!prevMonth) {
      return;
    }

    calendarBodyRef.scrollTo({
      top: 0,
      left: 0,
      behavior: 'smooth',
    });
  };

  private toggleMonthAndYearView = () => {
    this.showMonthAndYear = !this.showMonthAndYear;
  };

  /**
   * Universal render methods
   * These are pieces of datetime that
   * are rendered independently of presentation.
   */

  private renderFooter() {
    const { disabled, readonly, showDefaultButtons, showClearButton } = this;
    /**
     * The cancel, clear, and confirm buttons
     * should not be interactive if the datetime
     * is disabled or readonly.
     */
    const isButtonDisabled = disabled || readonly;
    const hasSlottedButtons = this.el.querySelector('[slot="buttons"]') !== null;
    if (!hasSlottedButtons && !showDefaultButtons && !showClearButton) {
      return;
    }

    const clearButtonClick = () => {
      this.reset();
      this.setValue(undefined);
    };

    /**
     * By default we render two buttons:
     * Cancel - Dismisses the datetime and
     * does not update the `value` prop.
     * OK - Dismisses the datetime and
     * updates the `value` prop.
     */
    return (
      <div class="datetime-footer">
        <div class="datetime-buttons">
          <div
            class={{
              ['datetime-action-buttons']: true,
              ['has-clear-button']: this.showClearButton,
            }}
          >
            <slot name="buttons">
              <ion-buttons>
                {showDefaultButtons && (
                  <ion-button
                    id="cancel-button"
                    color={this.color}
                    onClick={() => this.cancel(true)}
                    disabled={isButtonDisabled}
                  >
                    {this.cancelText}
                  </ion-button>
                )}
                <div class="datetime-action-buttons-container">
                  {showClearButton && (
                    <ion-button
                      id="clear-button"
                      color={this.color}
                      onClick={() => clearButtonClick()}
                      disabled={isButtonDisabled}
                    >
                      {this.clearText}
                    </ion-button>
                  )}
                  {showDefaultButtons && (
                    <ion-button
                      id="confirm-button"
                      color={this.color}
                      onClick={() => this.confirm(true)}
                      disabled={isButtonDisabled}
                    >
                      {this.doneText}
                    </ion-button>
                  )}
                </div>
              </ion-buttons>
            </slot>
          </div>
        </div>
      </div>
    );
  }

  /**
   * Wheel picker render methods
   */

  private renderWheelPicker(forcePresentation: string = this.presentation) {
    /**
     * If presentation="time-date" we switch the
     * order of the render array here instead of
     * manually reordering each date/time picker
     * column with CSS. This allows for additional
     * flexibility if we need to render subsets
     * of the date/time data or do additional ordering
     * within the child render functions.
     */
    const renderArray =
      forcePresentation === 'time-date'
        ? [this.renderTimePickerColumns(forcePresentation), this.renderDatePickerColumns(forcePresentation)]
        : [this.renderDatePickerColumns(forcePresentation), this.renderTimePickerColumns(forcePresentation)];
    return <ion-picker class={FOCUS_TRAP_DISABLE_CLASS}>{renderArray}</ion-picker>;
  }

  private renderDatePickerColumns(forcePresentation: string) {
    return forcePresentation === 'date-time' || forcePresentation === 'time-date'
      ? this.renderCombinedDatePickerColumn()
      : this.renderIndividualDatePickerColumns(forcePresentation);
  }

  private renderCombinedDatePickerColumn() {
    const { defaultParts, disabled, workingParts, locale, minParts, maxParts, todayParts, isDateEnabled } = this;

    const activePart = this.getActivePartsWithFallback();

    /**
     * By default, generate a range of 3 months:
     * Previous month, current month, and next month
     */
    const monthsToRender = generateMonths(workingParts);
    const lastMonth = monthsToRender[monthsToRender.length - 1];

    /**
     * Ensure that users can select the entire window of dates.
     */
    monthsToRender[0].day = 1;
    lastMonth.day = getNumDaysInMonth(lastMonth.month, lastMonth.year);

    /**
     * Narrow the dates rendered based on min/max dates (if any).
     * The `min` date is used if the min is after the generated min month.
     * The `max` date is used if the max is before the generated max month.
     * This ensures that the sliding window always stays at 3 months
     * but still allows future dates to be lazily rendered based on any min/max
     * constraints.
     */
    const min = minParts !== undefined && isAfter(minParts, monthsToRender[0]) ? minParts : monthsToRender[0];
    const max = maxParts !== undefined && isBefore(maxParts, lastMonth) ? maxParts : lastMonth;

    const result = getCombinedDateColumnData(
      locale,
      todayParts,
      min,
      max,
      this.parsedDayValues,
      this.parsedMonthValues
    );

    let items = result.items;
    const parts = result.parts;

    if (isDateEnabled) {
      items = items.map((itemObject, index) => {
        const referenceParts = parts[index];

        let disabled;
        try {
          /**
           * The `isDateEnabled` implementation is try-catch wrapped
           * to prevent exceptions in the user's function from
           * interrupting the calendar rendering.
           */
          disabled = !isDateEnabled(convertDataToISO(referenceParts));
        } catch (e) {
          printIonError(
            '[ion-datetime] - Exception thrown from provided `isDateEnabled` function. Please check your function and try again.',
            e
          );
        }

        return {
          ...itemObject,
          disabled,
        };
      });
    }

    /**
     * If we have selected a day already, then default the column
     * to that value. Otherwise, set it to the default date.
     */
    const todayString =
      workingParts.day !== null
        ? `${workingParts.year}-${workingParts.month}-${workingParts.day}`
        : `${defaultParts.year}-${defaultParts.month}-${defaultParts.day}`;

    return (
      <ion-picker-column
        aria-label="Select a date"
        class="date-column"
        color={this.color}
        disabled={disabled}
        value={todayString}
        onIonChange={(ev: CustomEvent) => {
          const { value } = ev.detail;
          const findPart = parts.find(({ month, day, year }) => value === `${year}-${month}-${day}`);

          this.setWorkingParts({
            ...workingParts,
            ...findPart,
          });

          this.setActiveParts({
            ...activePart,
            ...findPart,
          });

          ev.stopPropagation();
        }}
      >
        {items.map((item) => (
          <ion-picker-column-option
            part={item.value === todayString ? `${WHEEL_ITEM_PART} ${WHEEL_ITEM_ACTIVE_PART}` : WHEEL_ITEM_PART}
            key={item.value}
            disabled={item.disabled}
            value={item.value}
          >
            {item.text}
          </ion-picker-column-option>
        ))}
      </ion-picker-column>
    );
  }

  private renderIndividualDatePickerColumns(forcePresentation: string) {
    const { workingParts, isDateEnabled } = this;
    const shouldRenderMonths = forcePresentation !== 'year' && forcePresentation !== 'time';
    const months = shouldRenderMonths
      ? getMonthColumnData(this.locale, workingParts, this.minParts, this.maxParts, this.parsedMonthValues)
      : [];

    const shouldRenderDays = forcePresentation === 'date';
    let days = shouldRenderDays
      ? getDayColumnData(this.locale, workingParts, this.minParts, this.maxParts, this.parsedDayValues)
      : [];

    if (isDateEnabled) {
      days = days.map((dayObject) => {
        const { value } = dayObject;
        const valueNum = typeof value === 'string' ? parseInt(value) : value;
        const referenceParts: DatetimeParts = {
          month: workingParts.month,
          day: valueNum,
          year: workingParts.year,
        };

        let disabled;
        try {
          /**
           * The `isDateEnabled` implementation is try-catch wrapped
           * to prevent exceptions in the user's function from
           * interrupting the calendar rendering.
           */
          disabled = !isDateEnabled(convertDataToISO(referenceParts));
        } catch (e) {
          printIonError(
            '[ion-datetime] - Exception thrown from provided `isDateEnabled` function. Please check your function and try again.',
            e
          );
        }

        return {
          ...dayObject,
          disabled,
        };
      });
    }

    const shouldRenderYears = forcePresentation !== 'month' && forcePresentation !== 'time';
    const years = shouldRenderYears
      ? getYearColumnData(this.locale, this.defaultParts, this.minParts, this.maxParts, this.parsedYearValues)
      : [];

    /**
     * Certain locales show the day before the month.
     */
    const showMonthFirst = isMonthFirstLocale(this.locale, { month: 'numeric', day: 'numeric' });

    let renderArray = [];
    if (showMonthFirst) {
      renderArray = [
        this.renderMonthPickerColumn(months),
        this.renderDayPickerColumn(days),
        this.renderYearPickerColumn(years),
      ];
    } else {
      renderArray = [
        this.renderDayPickerColumn(days),
        this.renderMonthPickerColumn(months),
        this.renderYearPickerColumn(years),
      ];
    }

    return renderArray;
  }

  private renderDayPickerColumn(days: WheelColumnOption[]) {
    if (days.length === 0) {
      return [];
    }

    const { disabled, workingParts } = this;

    const activePart = this.getActivePartsWithFallback();
    const pickerColumnValue = (workingParts.day !== null ? workingParts.day : this.defaultParts.day) ?? undefined;

    return (
      <ion-picker-column
        aria-label="Select a day"
        class="day-column"
        color={this.color}
        disabled={disabled}
        value={pickerColumnValue}
        onIonChange={(ev: CustomEvent) => {
          this.setWorkingParts({
            ...workingParts,
            day: ev.detail.value,
          });

          this.setActiveParts({
            ...activePart,
            day: ev.detail.value,
          });

          ev.stopPropagation();
        }}
      >
        {days.map((day) => (
          <ion-picker-column-option
            part={day.value === pickerColumnValue ? `${WHEEL_ITEM_PART} ${WHEEL_ITEM_ACTIVE_PART}` : WHEEL_ITEM_PART}
            key={day.value}
            disabled={day.disabled}
            value={day.value}
          >
            {day.text}
          </ion-picker-column-option>
        ))}
      </ion-picker-column>
    );
  }

  private renderMonthPickerColumn(months: WheelColumnOption[]) {
    if (months.length === 0) {
      return [];
    }

    const { disabled, workingParts } = this;

    const activePart = this.getActivePartsWithFallback();

    return (
      <ion-picker-column
        aria-label="Select a month"
        class="month-column"
        color={this.color}
        disabled={disabled}
        value={workingParts.month}
        onIonChange={(ev: CustomEvent) => {
          this.setWorkingParts({
            ...workingParts,
            month: ev.detail.value,
          });

          this.setActiveParts({
            ...activePart,
            month: ev.detail.value,
          });

          ev.stopPropagation();
        }}
      >
        {months.map((month) => (
          <ion-picker-column-option
            part={month.value === workingParts.month ? `${WHEEL_ITEM_PART} ${WHEEL_ITEM_ACTIVE_PART}` : WHEEL_ITEM_PART}
            key={month.value}
            disabled={month.disabled}
            value={month.value}
          >
            {month.text}
          </ion-picker-column-option>
        ))}
      </ion-picker-column>
    );
  }
  private renderYearPickerColumn(years: WheelColumnOption[]) {
    if (years.length === 0) {
      return [];
    }

    const { disabled, workingParts } = this;

    const activePart = this.getActivePartsWithFallback();

    return (
      <ion-picker-column
        aria-label="Select a year"
        class="year-column"
        color={this.color}
        disabled={disabled}
        value={workingParts.year}
        onIonChange={(ev: CustomEvent) => {
          this.setWorkingParts({
            ...workingParts,
            year: ev.detail.value,
          });

          this.setActiveParts({
            ...activePart,
            year: ev.detail.value,
          });

          ev.stopPropagation();
        }}
      >
        {years.map((year) => (
          <ion-picker-column-option
            part={year.value === workingParts.year ? `${WHEEL_ITEM_PART} ${WHEEL_ITEM_ACTIVE_PART}` : WHEEL_ITEM_PART}
            key={year.value}
            disabled={year.disabled}
            value={year.value}
          >
            {year.text}
          </ion-picker-column-option>
        ))}
      </ion-picker-column>
    );
  }
  private renderTimePickerColumns(forcePresentation: string) {
    if (['date', 'month', 'month-year', 'year'].includes(forcePresentation)) {
      return [];
    }

    /**
     * If a user has not selected a date,
     * then we should show all times. If the
     * user has selected a date (even if it has
     * not been confirmed yet), we should apply
     * the max and min restrictions so that the
     * time picker shows values that are
     * appropriate for the selected date.
     */
    const activePart = this.getActivePart();
    const userHasSelectedDate = activePart !== undefined;

    const { hoursData, minutesData, dayPeriodData } = getTimeColumnsData(
      this.locale,
      this.workingParts,
      this.hourCycle,
      userHasSelectedDate ? this.minParts : undefined,
      userHasSelectedDate ? this.maxParts : undefined,
      this.parsedHourValues,
      this.parsedMinuteValues
    );

    return [
      this.renderHourPickerColumn(hoursData),
      this.renderMinutePickerColumn(minutesData),
      this.renderDayPeriodPickerColumn(dayPeriodData),
    ];
  }

  private renderHourPickerColumn(hoursData: WheelColumnOption[]) {
    const { disabled, workingParts } = this;
    if (hoursData.length === 0) return [];

    const activePart = this.getActivePartsWithFallback();

    return (
      <ion-picker-column
        aria-label="Select an hour"
        color={this.color}
        disabled={disabled}
        value={activePart.hour}
        numericInput
        onIonChange={(ev: CustomEvent) => {
          this.setWorkingParts({
            ...workingParts,
            hour: ev.detail.value,
          });

          this.setActiveParts({
            ...this.getActivePartsWithFallback(),
            hour: ev.detail.value,
          });

          ev.stopPropagation();
        }}
      >
        {hoursData.map((hour) => (
          <ion-picker-column-option
            part={hour.value === activePart.hour ? `${WHEEL_ITEM_PART} ${WHEEL_ITEM_ACTIVE_PART}` : WHEEL_ITEM_PART}
            key={hour.value}
            disabled={hour.disabled}
            value={hour.value}
          >
            {hour.text}
          </ion-picker-column-option>
        ))}
      </ion-picker-column>
    );
  }
  private renderMinutePickerColumn(minutesData: WheelColumnOption[]) {
    const { disabled, workingParts } = this;
    if (minutesData.length === 0) return [];

    const activePart = this.getActivePartsWithFallback();

    return (
      <ion-picker-column
        aria-label="Select a minute"
        color={this.color}
        disabled={disabled}
        value={activePart.minute}
        numericInput
        onIonChange={(ev: CustomEvent) => {
          this.setWorkingParts({
            ...workingParts,
            minute: ev.detail.value,
          });

          this.setActiveParts({
            ...this.getActivePartsWithFallback(),
            minute: ev.detail.value,
          });

          ev.stopPropagation();
        }}
      >
        {minutesData.map((minute) => (
          <ion-picker-column-option
            part={minute.value === activePart.minute ? `${WHEEL_ITEM_PART} ${WHEEL_ITEM_ACTIVE_PART}` : WHEEL_ITEM_PART}
            key={minute.value}
            disabled={minute.disabled}
            value={minute.value}
          >
            {minute.text}
          </ion-picker-column-option>
        ))}
      </ion-picker-column>
    );
  }
  private renderDayPeriodPickerColumn(dayPeriodData: WheelColumnOption[]) {
    const { disabled, workingParts } = this;
    if (dayPeriodData.length === 0) {
      return [];
    }

    const activePart = this.getActivePartsWithFallback();
    const isDayPeriodRTL = isLocaleDayPeriodRTL(this.locale);

    return (
      <ion-picker-column
        aria-label="Select a day period"
        style={isDayPeriodRTL ? { order: '-1' } : {}}
        color={this.color}
        disabled={disabled}
        value={activePart.ampm}
        onIonChange={(ev: CustomEvent) => {
          const hour = calculateHourFromAMPM(workingParts, ev.detail.value);

          this.setWorkingParts({
            ...workingParts,
            ampm: ev.detail.value,
            hour,
          });

          this.setActiveParts({
            ...this.getActivePartsWithFallback(),
            ampm: ev.detail.value,
            hour,
          });

          ev.stopPropagation();
        }}
      >
        {dayPeriodData.map((dayPeriod) => (
          <ion-picker-column-option
            part={
              dayPeriod.value === activePart.ampm ? `${WHEEL_ITEM_PART} ${WHEEL_ITEM_ACTIVE_PART}` : WHEEL_ITEM_PART
            }
            key={dayPeriod.value}
            disabled={dayPeriod.disabled}
            value={dayPeriod.value}
          >
            {dayPeriod.text}
          </ion-picker-column-option>
        ))}
      </ion-picker-column>
    );
  }

  private renderWheelView(forcePresentation?: string) {
    const { locale } = this;
    const showMonthFirst = isMonthFirstLocale(locale);
    const columnOrder = showMonthFirst ? 'month-first' : 'year-first';
    return (
      <div
        class={{
          [`wheel-order-${columnOrder}`]: true,
        }}
      >
        {this.renderWheelPicker(forcePresentation)}
      </div>
    );
  }

  /**
   * Grid Render Methods
   */

  private renderCalendarHeader(mode: Mode) {
    const { disabled } = this;
    const expandedIcon = mode === 'ios' ? chevronDown : caretUpSharp;
    const collapsedIcon = mode === 'ios' ? chevronForward : caretDownSharp;

    const prevMonthDisabled = disabled || isPrevMonthDisabled(this.workingParts, this.minParts, this.maxParts);
    const nextMonthDisabled = disabled || isNextMonthDisabled(this.workingParts, this.maxParts);

    // don't use the inheritAttributes util because it removes dir from the host, and we still need that
    const hostDir = this.el.getAttribute('dir') || undefined;

    return (
      <div class="calendar-header">
        <div class="calendar-action-buttons">
          <div class="calendar-month-year">
            <button
              class={{
                'calendar-month-year-toggle': true,
                'ion-activatable': true,
                'ion-focusable': true,
              }}
              part="month-year-button"
              disabled={disabled}
              aria-label={this.showMonthAndYear ? 'Hide year picker' : 'Show year picker'}
              onClick={() => this.toggleMonthAndYearView()}
            >
              <span id="toggle-wrapper">
                {getMonthAndYear(this.locale, this.workingParts)}
                <ion-icon
                  aria-hidden="true"
                  icon={this.showMonthAndYear ? expandedIcon : collapsedIcon}
                  lazy={false}
                  flipRtl={true}
                ></ion-icon>
              </span>
              {mode === 'md' && <ion-ripple-effect></ion-ripple-effect>}
            </button>
          </div>

          <div class="calendar-next-prev">
            <ion-buttons>
              <ion-button aria-label="Previous month" disabled={prevMonthDisabled} onClick={() => this.prevMonth()}>
                <ion-icon
                  dir={hostDir}
                  aria-hidden="true"
                  slot="icon-only"
                  icon={chevronBack}
                  lazy={false}
                  flipRtl
                ></ion-icon>
              </ion-button>
              <ion-button aria-label="Next month" disabled={nextMonthDisabled} onClick={() => this.nextMonth()}>
                <ion-icon
                  dir={hostDir}
                  aria-hidden="true"
                  slot="icon-only"
                  icon={chevronForward}
                  lazy={false}
                  flipRtl
                ></ion-icon>
              </ion-button>
            </ion-buttons>
          </div>
        </div>
        <div class="calendar-days-of-week" aria-hidden="true">
          {getDaysOfWeek(this.locale, mode, this.firstDayOfWeek % 7).map((d) => {
            return <div class="day-of-week">{d}</div>;
          })}
        </div>
      </div>
    );
  }
  private renderMonth(month: number, year: number) {
    const { disabled, readonly } = this;

    const yearAllowed = this.parsedYearValues === undefined || this.parsedYearValues.includes(year);
    const monthAllowed = this.parsedMonthValues === undefined || this.parsedMonthValues.includes(month);
    const isCalMonthDisabled = !yearAllowed || !monthAllowed;
    const isDatetimeDisabled = disabled || readonly;
    const swipeDisabled =
      disabled ||
      isMonthDisabled(
        {
          month,
          year,
          day: null,
        },
        {
          // The day is not used when checking if a month is disabled.
          // Users should be able to access the min or max month, even if the
          // min/max date is out of bounds (e.g. min is set to Feb 15, Feb should not be disabled).
          minParts: { ...this.minParts, day: null },
          maxParts: { ...this.maxParts, day: null },
        }
      );
    // The working month should never have swipe disabled.
    // Otherwise the CSS scroll snap will not work and the user
    // can free-scroll the calendar.
    const isWorkingMonth = this.workingParts.month === month && this.workingParts.year === year;

    const activePart = this.getActivePartsWithFallback();

    return (
      <div
        // Non-visible months should be hidden from screen readers
        aria-hidden={!isWorkingMonth ? 'true' : null}
        class={{
          'calendar-month': true,
          // Prevents scroll snap swipe gestures for months outside of the min/max bounds
          'calendar-month-disabled': !isWorkingMonth && swipeDisabled,
        }}
      >
        <div class="calendar-month-grid">
          {getDaysOfMonth(month, year, this.firstDayOfWeek % 7, this.showAdjacentDays).map((dateObject, index) => {
            const { day, dayOfWeek, isAdjacentDay } = dateObject;
            const { el, highlightedDates, isDateEnabled, multiple, showAdjacentDays } = this;
            let _month = month;
            let _year = year;
            if (showAdjacentDays && isAdjacentDay && day !== null) {
              if (day > 20) {
                // Leading with the adjacent day from the previous month
                // if its a adjacent day and is higher than '20' (last week even in feb)
                if (month === 1) {
                  _year = year - 1;
                  _month = 12;
                } else {
                  _month = month - 1;
                }
              } else if (day < 15) {
                // Leading with the adjacent day from the next month
                // if its a adjacent day and is lower than '15' (first two weeks)
                if (month === 12) {
                  _year = year + 1;
                  _month = 1;
                } else {
                  _month = month + 1;
                }
              }
            }

            const referenceParts = { month: _month, day, year: _year, isAdjacentDay };
            const isCalendarPadding = day === null;
            const {
              isActive,
              isToday,
              ariaLabel,
              ariaSelected,
              disabled: isDayDisabled,
              text,
            } = getCalendarDayState(
              this.locale,
              referenceParts,
              this.activeParts,
              this.todayParts,
              this.minParts,
              this.maxParts,
              this.parsedDayValues
            );

            const dateIsoString = convertDataToISO(referenceParts);

            let isCalDayDisabled = isCalMonthDisabled || isDayDisabled;

            if (!isCalDayDisabled && isDateEnabled !== undefined) {
              try {
                /**
                 * The `isDateEnabled` implementation is try-catch wrapped
                 * to prevent exceptions in the user's function from
                 * interrupting the calendar rendering.
                 */
                isCalDayDisabled = !isDateEnabled(dateIsoString);
              } catch (e) {
                printIonError(
                  '[ion-datetime] - Exception thrown from provided `isDateEnabled` function. Please check your function and try again.',
                  el,
                  e
                );
              }
            }

            /**
             * Some days are constrained through max & min or allowed dates
             * and also disabled because the component is readonly or disabled.
             * These need to be displayed differently.
             */
            const isCalDayConstrained = isCalDayDisabled && isDatetimeDisabled;

            const isButtonDisabled = isCalDayDisabled || isDatetimeDisabled;

            let dateStyle: DatetimeHighlightStyle | undefined = undefined;

            /**
             * Custom highlight styles should not override the style for selected dates,
             * nor apply to "filler days" at the start of the grid.
             */
            if (highlightedDates !== undefined && !isActive && day !== null && !isAdjacentDay) {
              dateStyle = getHighlightStyles(highlightedDates, dateIsoString, el);
            }

            let dateParts = undefined;

            // "Filler days" at the beginning of the grid should not get the calendar day
            // CSS parts added to them
            if (!isCalendarPadding && !isAdjacentDay) {
              dateParts = `calendar-day${isActive ? ' active' : ''}${isToday ? ' today' : ''}${
                isCalDayDisabled ? ' disabled' : ''
              }`;
            } else if (isAdjacentDay) {
              dateParts = `calendar-day${isCalDayDisabled ? ' disabled' : ''}`;
            }

            return (
              <div class="calendar-day-wrapper">
                <button
                  // We need to use !important for the inline styles here because
                  // otherwise the CSS shadow parts will override these styles.
                  // See https://github.com/WICG/webcomponents/issues/847
                  // Both the CSS shadow parts and highlightedDates styles are
                  // provided by the developer, but highlightedDates styles should
                  // always take priority.
                  ref={(el) => {
                    if (el) {
                      el.style.setProperty('color', `${dateStyle ? dateStyle.textColor : ''}`, 'important');
                      el.style.setProperty(
                        'background-color',
                        `${dateStyle ? dateStyle.backgroundColor : ''}`,
                        'important'
                      );
                      el.style.setProperty('border', `${dateStyle ? dateStyle.border : ''}`, 'important');
                    }
                  }}
                  tabindex="-1"
                  data-day={day}
                  data-month={_month}
                  data-year={_year}
                  data-index={index}
                  data-day-of-week={dayOfWeek}
                  disabled={isButtonDisabled}
                  class={{
                    'calendar-day-padding': isCalendarPadding,
                    'calendar-day': true,
                    'calendar-day-active': isActive,
                    'calendar-day-constrained': isCalDayConstrained,
                    'calendar-day-today': isToday,
                    'calendar-day-adjacent-day': isAdjacentDay,
                  }}
                  part={dateParts}
                  aria-hidden={isCalendarPadding ? 'true' : null}
                  aria-selected={ariaSelected}
                  aria-label={ariaLabel}
                  onClick={() => {
                    if (isCalendarPadding) {
                      return;
                    }

                    if (isAdjacentDay) {
                      // The user selected a day outside the current month. Ignore this button, as the month will be re-rendered.
                      this.el.blur();
                      this.activeParts = { ...activePart, ...referenceParts };
                      this.animateToDate(referenceParts);
                      this.confirm();
                    } else {
                      this.setWorkingParts({
                        ...this.workingParts,
                        ...referenceParts,
                      });

                      // Multiple only needs date info so we can wipe out other fields like time.
                      if (multiple) {
                        this.setActiveParts(referenceParts, isActive);
                      } else {
                        this.setActiveParts({
                          ...activePart,
                          ...referenceParts,
                        });
                      }
                    }
                  }}
                >
                  {text}
                </button>
              </div>
            );
          })}
        </div>
      </div>
    );
  }
  private renderCalendarBody() {
    return (
      <div class="calendar-body ion-focusable" ref={(el) => (this.calendarBodyRef = el)} tabindex="0">
        {generateMonths(this.workingParts, this.forceRenderDate).map(({ month, year }) => {
          return this.renderMonth(month, year);
        })}
      </div>
    );
  }
  private renderCalendar(mode: Mode) {
    return (
      <div class="datetime-calendar" key="datetime-calendar">
        {this.renderCalendarHeader(mode)}
        {this.renderCalendarBody()}
      </div>
    );
  }
  private renderTimeLabel() {
    const hasSlottedTimeLabel = this.el.querySelector('[slot="time-label"]') !== null;
    if (!hasSlottedTimeLabel && !this.showDefaultTimeLabel) {
      return;
    }

    return <slot name="time-label">Time</slot>;
  }

  private renderTimeOverlay() {
    const { disabled, hourCycle, isTimePopoverOpen, locale, formatOptions } = this;
    const computedHourCycle = getHourCycle(locale, hourCycle);
    const activePart = this.getActivePartsWithFallback();

    return [
      <div class="time-header">{this.renderTimeLabel()}</div>,
      <button
        class={{
          'time-body': true,
          'time-body-active': isTimePopoverOpen,
        }}
        part={`time-button${isTimePopoverOpen ? ' active' : ''}`}
        aria-expanded="false"
        aria-haspopup="true"
        disabled={disabled}
        onClick={async (ev) => {
          const { popoverRef } = this;

          if (popoverRef) {
            this.isTimePopoverOpen = true;

            popoverRef.present(
              new CustomEvent('ionShadowTarget', {
                detail: {
                  ionShadowTarget: ev.target,
                },
              })
            );

            await popoverRef.onWillDismiss();

            this.isTimePopoverOpen = false;
          }
        }}
      >
        {getLocalizedTime(locale, activePart, computedHourCycle, formatOptions?.time)}
      </button>,
      <ion-popover
        alignment="center"
        translucent
        overlayIndex={1}
        arrow={false}
        onWillPresent={(ev) => {
          /**
           * Intersection Observers do not consistently fire between Blink and Webkit
           * when toggling the visibility of the popover and trying to scroll the picker
           * column to the correct time value.
           *
           * This will correctly scroll the element position to the correct time value,
           * before the popover is fully presented.
           */
          const cols = (ev.target! as HTMLElement).querySelectorAll('ion-picker-column');
          // TODO (FW-615): Potentially remove this when intersection observers are fixed in picker column
          cols.forEach((col) => col.scrollActiveItemIntoView());
        }}
        style={{
          '--offset-y': '-10px',
          '--min-width': 'fit-content',
        }}
        // Allow native browser keyboard events to support up/down/home/end key
        // navigation within the time picker.
        keyboardEvents
        ref={(el) => (this.popoverRef = el)}
      >
        {this.renderWheelPicker('time')}
      </ion-popover>,
    ];
  }

  private getHeaderSelectedDateText() {
    const { activeParts, formatOptions, multiple, titleSelectedDatesFormatter } = this;
    const isArray = Array.isArray(activeParts);

    let headerText: string;
    if (multiple && isArray && activeParts.length !== 1) {
      headerText = `${activeParts.length} days`; // default/fallback for multiple selection
      if (titleSelectedDatesFormatter !== undefined) {
        try {
          headerText = titleSelectedDatesFormatter(convertDataToISO(activeParts));
        } catch (e) {
          printIonError('[ion-datetime] - Exception in provided `titleSelectedDatesFormatter`:', e);
        }
      }
    } else {
      // for exactly 1 day selected (multiple set or not), show a formatted version of that
      headerText = getLocalizedDateTime(
        this.locale,
        this.getActivePartsWithFallback(),
        formatOptions?.date ?? { weekday: 'short', month: 'short', day: 'numeric' }
      );
    }

    return headerText;
  }

  private renderHeader(showExpandedHeader = true) {
    const hasSlottedTitle = this.el.querySelector('[slot="title"]') !== null;
    if (!hasSlottedTitle && !this.showDefaultTitle) {
      return;
    }

    return (
      <div class="datetime-header">
        <div class="datetime-title">
          <slot name="title">Select Date</slot>
        </div>
        {showExpandedHeader && <div class="datetime-selected-date">{this.getHeaderSelectedDateText()}</div>}
      </div>
    );
  }

  /**
   * Render time picker inside of datetime.
   * Do not pass color prop to segment on
   * iOS mode. MD segment has been customized and
   * should take on the color prop, but iOS
   * should just be the default segment.
   */
  private renderTime() {
    const { presentation } = this;
    const timeOnlyPresentation = presentation === 'time';

    return (
      <div class="datetime-time">{timeOnlyPresentation ? this.renderWheelPicker() : this.renderTimeOverlay()}</div>
    );
  }

  /**
   * Renders the month/year picker that is
   * displayed on the calendar grid.
   * The .datetime-year class has additional
   * styles that let us show/hide the
   * picker when the user clicks on the
   * toggle in the calendar header.
   */
  private renderCalendarViewMonthYearPicker() {
    return <div class="datetime-year">{this.renderWheelView('month-year')}</div>;
  }

  /**
   * Render entry point
   * All presentation types are rendered from here.
   */

  private renderDatetime(mode: Mode) {
    const { presentation, preferWheel } = this;

    /**
     * Certain presentation types have separate grid and wheel displays.
     * If preferWheel is true then we should show a wheel picker instead.
     */
    const hasWheelVariant = presentation === 'date' || presentation === 'date-time' || presentation === 'time-date';
    if (preferWheel && hasWheelVariant) {
      return [this.renderHeader(false), this.renderWheelView(), this.renderFooter()];
    }

    switch (presentation) {
      case 'date-time':
        return [
          this.renderHeader(),
          this.renderCalendar(mode),
          this.renderCalendarViewMonthYearPicker(),
          this.renderTime(),
          this.renderFooter(),
        ];
      case 'time-date':
        return [
          this.renderHeader(),
          this.renderTime(),
          this.renderCalendar(mode),
          this.renderCalendarViewMonthYearPicker(),
          this.renderFooter(),
        ];
      case 'time':
        return [this.renderHeader(false), this.renderTime(), this.renderFooter()];
      case 'month':
      case 'month-year':
      case 'year':
        return [this.renderHeader(false), this.renderWheelView(), this.renderFooter()];
      default:
        return [
          this.renderHeader(),
          this.renderCalendar(mode),
          this.renderCalendarViewMonthYearPicker(),
          this.renderFooter(),
        ];
    }
  }

  render() {
    const {
      name,
      value,
      disabled,
      el,
      color,
      readonly,
      showMonthAndYear,
      preferWheel,
      presentation,
      size,
      isGridStyle,
    } = this;
    const mode = getIonMode(this);
    const isMonthAndYearPresentation =
      presentation === 'year' || presentation === 'month' || presentation === 'month-year';
    const shouldShowMonthAndYear = showMonthAndYear || isMonthAndYearPresentation;
    const monthYearPickerOpen = showMonthAndYear && !isMonthAndYearPresentation;
    const hasDatePresentation = presentation === 'date' || presentation === 'date-time' || presentation === 'time-date';
    const hasWheelVariant = hasDatePresentation && preferWheel;

    renderHiddenInput(true, el, name, formatValue(value), disabled);

    return (
      <Host
        aria-disabled={disabled ? 'true' : null}
        onFocus={this.onFocus}
        onBlur={this.onBlur}
        class={{
          ...createColorClasses(color, {
            [mode]: true,
            ['datetime-readonly']: readonly,
            ['datetime-disabled']: disabled,
            'show-month-and-year': shouldShowMonthAndYear,
            'month-year-picker-open': monthYearPickerOpen,
            [`datetime-presentation-${presentation}`]: true,
            [`datetime-size-${size}`]: true,
            [`datetime-prefer-wheel`]: hasWheelVariant,
            [`datetime-grid`]: isGridStyle,
          }),
        }}
      >
        {/*
          WebKit has a quirk where IntersectionObserver callbacks are delayed until after
          an accelerated animation finishes if the "root" specified in the config is the
          browser viewport (the default behavior if "root" is not specified). This means
          that when presenting a datetime in a modal on iOS the calendar body appears
          blank until the modal animation finishes.

          We can work around this by observing .intersection-tracker and using the host
          (ion-datetime) as the "root". This allows the IO callback to fire the moment
          the datetime is visible. The .intersection-tracker element should not have
          dimensions or additional styles, and it should not be positioned absolutely
          otherwise the IO callback may fire at unexpected times.
        */}
        <div class="intersection-tracker" ref={(el) => (this.intersectionTrackerRef = el)}></div>
        {this.renderDatetime(mode)}
      </Host>
    );
  }
}

let datetimeIds = 0;
const CANCEL_ROLE = 'datetime-cancel';
const CONFIRM_ROLE = 'datetime-confirm';
const WHEEL_ITEM_PART = 'wheel-item';
const WHEEL_ITEM_ACTIVE_PART = `active`;
